/**
* 精灵类
* 选择支，菜单界面的定义
*
*/
var sprite = function (width, height, src) {
	var sp = $('#menu')[0].getContext('2d'),
		width = width,
		heigh = height,
		image = new Image();
	image.src = src;
	var that = {
			draw: function(x, y) {
				sp.drawImage(image, x, y, width, height);
				$top = $('#top').append(<div/>).find(':last');
			}
	}
	return that;
}